The db2top tool is all about showing the top sessions, bufferpools,
tablespaces, etc. by some criteria. It wouldn’t be very useful if it
didn’t let you choose these criteria. Fortunately, db2top lets you
quickly base the order in which the data is presented on the criteria of
your choice. In today’s post, we’ll see how.Click here to read the rest of "db2top Sort" at Keith's blog

On a busy system, sometimes the amount of data returned by our
monitoring tools can be overwhelming. Fortunately, db2top was designed
with this in mind and has a very flexible and powerful feature for
extracting the information critical to your decision-making from reams
of monitoring data. This feature, called regular expressions, is the
subject of today’s post.Click here to read the rest of this post on db2top Filters at Keith's blog

Have you ever spent a long time trying to figure out what was causing
DB2 to give you a bizarre error message only to find that the root cause
was a default you didn’t know was a default? I got just such a message
the other day when writing an SQL stored procedure. In this post, I will
show you the confusing message I encountered and give you the
opportunity to see if you can figure out the solution.Click here to read the rest of DB2 Stored Procedures and Defaults at Keith's blog

As we saw when we examined its background
and collection
modes, db2top is not just a tool for letting you observe a running
system – it also lets you record activity for later analysis. Another
way to record data for later is the db2top Watch feature, which lets you
precisely specify which SQL statements you want to collect. With this
feature, for example, you could watch only those SQL statements coming
from a particular application or user. In today’s post, we will get to
see the flexibility of the db2top Watch feature as we learn how to:

Now that I have concluded my posts on the data screens of db2top, I
am creating a new page on my site for easy access to a table of
contents listing all of the articles I have written so far. You can
reach it at any time by clicking the db2top link at the top left of
my site (www.thekguy.com):

Starting next week, I will begin to address the remaining features in
the product, including a sort feature, a filter feature, and many
others.

In a DB2 for LUW database that makes use of the data partitioning
feature available in the Infosphere Warehouse product, one of the new
concerns a database administrator is faced with is skew among the
partitions. Adding or removing partitions from a database introduces
skew and requires a redistribution to ensure data is spread evenly
across all partitions. Typically, it is desirable to reduce skew in
order to balance the use of storage space and improve database system
performance.

In some cases, however, an unequal distribution of data can be
desirable. To use an example from the DB2
9.7 documentation, if some database partitions reside on a
particularly powerful machine, then it may be beneficial for those
database partitions to contain larger volumes of data than other
partitions.

To determine data skew, the same documentation recommends using a
query like the following on a representative table in a partition group:

SELECT DBPARTITIONNUM(column_name), COUNT(*) FROM table_name
GROUP BY DBPARTITIONNUM(column_name)
ORDER BY DBPARTITIONNUM(column_name) DESC

where column_name is the name of the distribution key for table
table_name. Another option for determining data skew is the ANALYZE_LOG_SPACE
procedure.

Another form of skew to examine is skew in your data access patterns.
You can observe data access skew by looking at how the data actually
gets used, that is, to see if more data is being read from one partition
than the others by the queries being run by the users of the database.
In today’s post, we will investigate the Skew screen of db2top and learn
what it can tell you about data access skew in your database.Click here to read the rest of this post on the db2top Skew Screen at Keith's blog

The db2top Bottlenecks screen lets us see who the biggest consumers of
each resource are and how much of the resource they are consuming. These
top consumers can often cause such resources to become bottlenecked, so
the Bottlenecks screen gives you an easy way to find the cause of such
bottlenecks so that you can take action. Today, we will examine each of
the individual resources for which the bottleneck screen reports the
biggest consumer and how much it consumes.Click here to read the rest of this post on the db2top Bottlenecks Screen part 2

A database workload performs at its best when resources are made
available to it in all the right proportions. Having any one resource
constrained too much and everything slows down. You can have more CPU
cycles available than you’ll ever need, but if your IO subsystem can’t
keep up with the work, it becomes a bottleneck and you’ll never achieve
your desired throughput. In today’s post, we’ll take a look at the
db2top Bottlenecks screen and see how it can help you find and resolve
bottlenecks in your system by finding the top consumers of each of the
major system resources.Click here to read the rest of this post on the db2top Bottlenecks Screen (Part 1) at Keith's blog

Today’s topic is db2top’s Federation screen. Federation is a technology
that allows you to build a heterogeneous set of database management
systems into a single interface without requiring you to move all your
data into one database. DB2 for LUW federation lets you query and
perform transactions against Oracle, DB2 for z/OS, Microsoft SQL Server,
or even another DB2 for LUW system. In today’s post, I will show you
how to set up a simple federated system that connects to a DB2 for LUW
data source and we will see how to monitor it with the db2top Federated
screen.Click here to read the rest of the post on the db2top Federation Screen at Keith's blog

A colleague of mine asked me the other day if I knew whether db2top
reported storage path information anywhere. He knew that the information
was being read from the snapshots but couldn’t see it anywhere in the
db2top interface. My first thought was that the table spaces screen
might have something like that but I couldn’t recall anything. So I went to www.thekguy.com, typed “storage path” into the site search box (on the
upper right corner of most pages of the site) and pressed Enter.
Lo and behold, it gave me an answer I wasn’t expecting but was
exactly what I needed.Continue reading the post "Don't Forget About The Site Search Feature!" at Keith's blog